A simple and accurate method was developed for sampling the immature stages of Aedes togoi in rock pools. As the distribution of this mosquito is contagious in water, the number of larvae and pupae caught by the conventional dipping method, in which surface water is collected by a dipper, is variable among samplings. But by stirring well the water in a jar, the distribution pattern became uniform, and nearly the same number of larvae and pupae could be collected by any dipping. The ratio of the number of immature stages of mosquitoes caught by a dipper to the whole number of them in the jar was exactly equivalent to the ratio of the volume of the dipper to that of the water in the jar.